This is a guide for students attempting Representing Data using Bits in digital technologies achievement standard 1.44 (AS91074). You will need to cover **two**different types of data to meet the requirements of the standard (each assessment guide only covers one). See the introduction for the 2.44 guides for more details on choosing topics; this guide covers the “images/colour” type of data. In order to fully cover the standard, you will also need to have done one more project for representing data using bits and projects covering the topics of *Encoding*and *Human Computer Interaction*, and included these in your report. ## 17.12.1\. OVERVIEW The topic of representing data using bits has the following bullet points in achievement standard 1.44, which this guide covers. Note that there is no excellence criteria for this topic. This assessment guide only covers one of the two types of data required for achieved. **Achieved**: “describing ways in which different types of data **Merit**: “comparing and contrasting different ways in which different types of data can be represented using bits and discussing the implications” As with all externally assessed reports, you should base your explanations around personalised examples. ## 17.12.2\. READING FROM THE COMPUTER SCIENCE FIELD GUIDE You should read and work through the interactives in the following sections of the CS Field Guide in order to prepare yourself for the assessed project. Read all of these sections, as they give the necessary introduction of the topic 5.1 - What’s the Big Picture? (General information about bits) 5.4 - Representing Numbers With Bits (Relevant to the achieved criteria) 5.6 - Representing Images With Bits (Relevant to the achieved criteria) 5.6.1 - Representing High Quality Images Using Bits (Relevant to the achieved criteria) 5.6.3 - Representing colours using fewer bits (Relevant to the merit criteria) ## 17.12.3\. PROJECT ### 17.12.3.1\. WRITING YOUR REPORT **Achieved** Using the colour matcher (note that it is at the start of section 5.6.3), choose a colour you like by clicking on the image. Try and match up the 24 bit colour hexagon to be the same colour as your selected colour. Don’t worry about the 8 bit hexagon yet. If you have trouble, the interactive will help you. Once you have matched up the colour, make a screenshot of the colour matcher which you can include in your report. You should now have 3 numbers; one for each of red, green, and blue. Convert each of these numbers into 8 bit binary numbers. These 3 numbers put together make up the 24 bit number that represents your colour. Show your working in your report, and explain how you arrived at your answer. **Merit** For merit, you need to show what happens when fewer bits are used to represent each colour in an image. There are several ways you can go about this; we recommend exploring the various interactives on colour representation and experimenting with them. Include at least one screenshot of an interactive and your personalised example which shows what happens when fewer bits are used to represent the colours in the image. What is the benefit of using fewer bits? What happens to the images when fewer bits are used? Are there certain kinds of images where it matters a lot? Are there other cases where the benefits of fewer bits outweigh the downsides? ## 17.12.4\. HINTS FOR SUCCESS * Remember that this part of the standard only goes up to the merit level. While you need to do some evaluation for merit, you should be mindful that the other topics go up to the excellence level, so they should make up the bulk of your in depth evaluations. * Remember to do a second project on a different type of data * You may need to reread the section on representing numbers using bits if you cannot remember how to convert the numbers into binary. Additionally you could also look at the worked example for the large block of purple in the previous section. * Choose a colour that has at least two of the three colour components somewhere in the middle of the slider. Examples such as 0, 255, and 1 are not helpful for showing your knowledge of binary representation. * Make sure the screenshots are large enough to be seen, but no larger! ## 17.12.5\. RECOMMENDED NUMBER OF PAGES We recommend that this project does not take up more than 1 page. Examples should be small, and discussions should be short and to the point, keeping in mind that there is no excellence criteria for this topic.